See https://github.com/ggerganov/whisper.cpp/blob/00b7a4be02ca82d53ac69dd2dd438c16e2af7658/whisper.h#L433C19-L433C19 for details.
Language code, e.g. "en", "de", "fr", "es", "it", "nl", "pt", "ru", "tr", "uk", "pl", "sv", "cs", "zh", "ja", "ko"
See https://github.com/ggerganov/whisper.cpp/blob/00b7a4be02ca82d53ac69dd2dd438c16e2af7658/whisper.h#L433C19-L433C19 for details.